Fun for a while, with very easy achievements...
For those un-acquainted with Galaga, it's a space shooter that's rather simple, but was popular because of the challenging AI and plenty of levels. The gameplay sticks to the original, as do the graphics. There are over 200 levels, but to get all of the achiements, one only has to get as far as the 31st.
The achievements are one of the easiest of any arcade games, most players will get around half in their first play. None require you to get too far in the game, and with the new option of starting at any level you've been to, it doesn't take long before you have an extra 200 gamerscore.
The music is non-existant, and the sound effects become repetitive. Notifications (when friends log on) tend to get right in the way, causing some frustrating problems.
At $5, Galaga is worth the buy for 200 GS, and to relive old days at the arcade. The gameplay is fun, and worth playing a lot for a high score. The gamerpoints don't really motivate, but it's definately worth-while.